Optimisation of Injection Moulding Parameter towards Shrinkage and Warpage for Polypropylene-Nanoclay-Gigantochloa Scortechinii Nanocomposites

Abstract

The setting of suitable parameter's level and values were very crucial in determining the quality characteristic of the injection moulding's product, especially made from advanced polymer nanocomposites. Therefore, this research was proposed to optimise the injection moulding parameters towards the quality characteristics of samples made from polypropylene-nanoclay-Gigantochloa Scortechinii fibers. The quality characteristics that need to be controlled were shrinkage and warpage, and the selected parameters were packing pressure, barrel temperature, screw speed and filling time. The Gigantochloa Scortechinii fibers need to be preheated at 1200C first, and then mixed with polypropylene, polypropylene grafted maleic anhydride and nanoclay through the compounding process by using Brabender Plastograph. The injection moulding process was performed based on the orthogonal array from Taguchi Optimisation Method. According to the results, the value of warpage was reduced when the fiber content was increased from 1wt. % to 3wt. %. The warpage value changed from 0.025mm to 0.009mm. The optimum parameter for warpage were 175°C barrel temperature, 40% packing pressure, 35% screw speed and 2seconds filling time for both 1wt. % and 3% of GS fiber. However, in terms of shrinkage, the increment of fiber content doesn’t have much impact towards the response. The value of shrinkage was reduced but not significantly from 0.0136mm to 0.0134mm when the percentage of fiber was added. The optimum parameter for 1wt. % fiber to control shrinkage are 170°C melt temperature, 35% packing pressure, 30% screw speed and 2seconds of filling time. The findings of this research will be valuable for quality control and references for products made from polypropylene-nanoclay-Gigantochloa Scortechinii fibers.